1. Field of Invention
The present invention relates to an apparatus for storing electrical energy. More particularly, the present invention relates to a magnetic capacitor for storing electrical energy.
2. Description of Related Art
Energy storage parts play important roles in our daily life since they influence the performance and the working time of electrical devices. Components such as capacitors used in the circuits and batteries used in portable devices are the most common energy storage parts.
The Giant Magnetoresistance Effect (GMR) is a quantum mechanical effect observed in structures with alternating thin magnetic and thin nonmagnetic sections. The GMR effect shows a significant change in electrical resistance from the zero-field high resistance state to the high-field low resistance state according to an applied external field.
Therefore, the GMR effect can be used to as an insulator with good performance. Thus, the apparatus with the GMR effect can be implemented to store electrical energy. A magnetic capacitor is an example of the apparatus with the GMR effect. Magnetic capacitors are formed with magnetic plates. A magnetic plate has a north pole and a south pole, and the north pole and south pole have the strongest magnetic field along the magnetic plate. In reality, the magnetic field strength is summarized and combined with all magnetic dipoles along easy axis. Please refer to FIG. 1A FIG. 1A shows localized dipoles of magnetic plates in a magnetic capacitor. The magnetic capacitor includes a first magnetic plate 110, a second magnetic plate 120, and a dielectric layer 130. The first magnetic plate 110 and the second magnetic plate 120 have dipoles pointing in the same directions.
Refer to FIG. 1B. FIG. 1B shows a magnetic plate and the magnetic field contour of the magnetic plate showing the field strength intensity. The density of the magnetic field lines in the magnetic field contour represents the magnetic field strength. As shown in FIG. 1B, the magnetic field strength decreases from two sides of the magnet plate. Due to the magnetic field effect, magnetic capacitors have shown colossal capacitance. Therefore the colossal magnetic effect is reduced from the edge to the center of the magnet plate. However, as the sizes of electrical devices continue to shrink, the need to store more capacitance in a limited area is rising.
For the foregoing reasons, there is a need to have an apparatus with the GMR effect and large capacitance values to store electrical energy.